Hishamuddin said that investigators were "cautiously hopeful" that there would be more news within "days, if not hours" about whether the signals consistent with transmissions from aircraft black boxes detected Sunday were related to the missing airliner.

“I urge all Malaysians to unite in their prayers and not give up hope,” he added. “We have been through a real rollercoaster ride on some of the leads we have received. I am more optimistic about this one.”

The Beijing-bound Boeing 777 was carrying 239 people when it vanished on March 8.